The Centre's deputy coordinator, Edwina Kotoisuva, says current the prison sentences are too lenient given the severity of the crime.

She says although the possible maximum term is 25 years, sentences ranges anywhere from 18 months to five years.

And she says the number of young offenders is a worry.

"We have got juveniles involved and it has been a trend over the past few years, and we wouldn't want them to go through a prison system that ends up bringing them out as harsher criminals. What we would like is some sort of re-education process."

Edwina Kotoisuva says there has been a rise in the number of rape and sexual assault cases, with 136 reported to the centre last year.